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Could liquid air energy storage address periods of over-supply from renewables?

Posted by Jason Ramsdale on 4 December 2015 at 1:10 pm

One of our readers recently responded to our blog on "When will the level playing field be ready for renewables to compete on?" with the following email:

Dear YouGen,

Regarding your article about the National Grid being unable to absorb excess power generated by renewable sources during periods of over-supply, it is very noticeable in the area where I live (Fife) that the various wind-farms here have several turbines regularly shut down in these circumstances for which I understand compensation payments are made.

This is not a good advert for renewable energy and gives justifiable opposition to opponents of the various technologies who see it as too intermittent for practical use.

In case you have not looked at this already, a solution has been worked on for some years using cryogenic storage of air which subsequently drives an electrical generator when the stored energy is required. A 5MW test system is based at Highview Power and this may be of interest to readers.

There is further information on the subject which suggests a 60-70% round cycle is now technically feasible – much better than the 25% round cycle for Hydrogen technologies.

I have no connection with any if the companies involved on this subject and my only interest is as a detached observer.

Brian Griffiths

Liquid Air Energy Storage (LAES)

I'd like to start by thanking Brian on the behalf of YouGen for an insightful and informative response. LAES uses off-peak or excess electricity to power an air liquefier, which produces liquid air. This liquid air can be stored in tanks at low pressure. At times of high demand the liquid air is pumped to high pressure, evaporated and heated. As this high pressure gas is released it drives a turbine to generate electricity.

liquid_energy_storage

Advantages of Liquid Air Energy Storage

  • LAES boasts competitive pricing with low capital and operating costs 
  • Unlike traditional air storage which uses underground caverns LAES can be sited anywhere
  • Unlike battery storage, LAES sites have a long life expectancy (25+ years)
  • You can integrate waste industrial heat and cold to improve the system
  • High density, clean energy. No scarce materials or harmful emissions

Disadvantages of Liquid Air Energy Storage

  • Less efficient than battery and pumped-hydro storage
  • Grid-scale technology, not easily implemented for communities and individual homeowners
  • Takes a few seconds to minutes longer than batteries to respond to power demand.

Highview Power Storage have the worlds first operation LAES here in the UK:

Some of the recent developments in LAES such as water spray cooling are said to increase the efficiency and lower the costs of compression and are discussed by Danielle Fong co-founder of LightSail Energy in a TEDxTalk:

It is an exciting prospect that this technology has the potential to make renewable energy just as reliable and flexible as traditional fossil fuel and nuclear power.  Cost-effective and easy to implement large-scale energy storage can only be seen as positive news for renewable energy generation.

Images:Highview Power Storage on Flickr and brochure.

More information about Energy Storage on YouGen

Find an Energy Storage installer.

Need help with any Jargon?

If you have a question about anything in the above blog, please ask it in the comments section below.

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Comments

2 comments - read them below or add one

Gordon Glass

Gordon Glass from Comment left on: 3 January 2017 at 12:10 pm

@solar wind. The original blog predicted a future time when the renewable electricity available to the UK grid might exceed the grid's capacity to absorb it and have people use it in real time. I think this is some way in the future for the UK, so I doubt it is the best explanation for the odd wind turbines on shutdown that Brian mentions in his letter. Perhaps a wind farm manager can enlighten us on the most common reason for turbines being shutdown, where not for maintenance or for lack of optimal wind conditions?

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Solar Wind

Solar WindComment left on: 21 December 2016 at 10:27 am

Is this article true. National Grid is the national grid that moves generation to wherever it is needed. That is the point of having a national grid, as generation is never going to be where it is needed.

Most people think of National Grid as their local grid and it is not. The national grid is normally 400,000 or 275,000 volts.

The local grids into which wind turbines and solar PV feeds are much lower at 11,000 or 33,000 volts, so the two should not be confused.

I doubt any wind turbine or solar PV installation is directly connected to the national grid, but only connected to the local grid. Probably anything less that 50 or 100MW would be insignificant in terms of national generation. Local grids however may have stability problems with over supply but any installation has to have approval of the Local Distribution Network Operator before they are allowed to connect for this very reason.

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